Executive function declines long-term after 'transient' brain attacks

(Reuters Health) - People who have so-called transient neurological attacks, including brief mini-strokes, may develop cognitive problems that linger for months, a recent study suggests.

Dutch researchers looked at long-term mental functioning in people who had experienced brief neurological attacks, which can occur when blood vessels in the brain are damaged or temporarily blocked and include transient ischemic attacks (TIAs), often called mini-strokes.

The study team did brain scans and cognitive assessments of 150 people within a few days after the patients had a transient neurological attack. In cognitive tests repeated six months later, participants did worse in executive function skills needed for things like attention and time management.

“Executive function is less visible compared to walking and talking, but the latter may be given most attention in the acute phase,” said senior study author Dr. Ewoud van Dijk of Radboud University Nijmegen Medical Center in the Netherlands.

During a mini-stroke, or TIA, people may notice the sudden onset of symptoms like numbness or weakness in the arm, leg or face, especially on one side of the body; confusion or difficulty talking; vision problems or dizziness and loss of balance. These symptoms often clear up within 24 hours.

While previous research has also linked mini-stroke to a decline in executive function, the current study findings suggest that subtle changes in the brain may occur that aren’t immediately detectable.

Patients in the study were 65 years old on average.

Overall, 73 participants, or 60 percent, were diagnosed with mini-stroke, and the remaining 48 patients were diagnosed with other types of transient neurological attack.

Brain scans done at the start of the study showed 32 patients had brain lesions, or abnormal tissue, which can include damage to blood vessels and cells.

On cognitive tests done at the start of the study, people with brain lesions scored worse on every type of function assessment compared to patients without lesions, the researchers report in Stroke.

But after accounting for other factors that could influence these results such as age, sex, and education, the only difference that was still statistically meaningful was the lag in executive function.

More research is needed to determine exactly how a mini-stroke might lead to diminished executive function and to get a better understanding of which patients are at highest risk, van Dijk said by email.

The study wasn’t a controlled experiment designed to prove whether or how a mini-stroke contributes to cognitive problems in general or deficits in executive function in particular.

Beyond its small size, another limitation is the relatively young and healthy group of participants, which may have led researchers to underestimate the magnitude of cognitive problems that can follow a mini-stroke, the authors note.

“This small study underscores the need for future trials to determine whether executive function continues to decline further out from the stroke such as 1 or 2 years,” said Sandra Billinger, a stroke researcher at Kansas University Medical Center in Kansas City who wasn’t involved in the study.

Patients should still be alert for potential changes, though, because many people don’t necessarily have a follow-up appointment after a mini-stroke and any decline in thinking abilities might not be noticed until later, Billinger said by email.

Ideally, patients can work to prevent a mini-stroke by doing things that are healthy for their brain and heart, like controlling their blood pressure and keeping physically and mentally fit, said Sarah Pendlebury, a neuroscience researcher at the University of Oxford in the UK who wasn’t involved in the study.

If they do have a mini-stroke, they can still do these things to try to minimize the odds of another one, Pendlebury said by email.

“There needs to be robust secondary prevention treatment to reduce the risk of another and possibly more major event,” Pendlebury added. “At the moment there is no specific treatment for executive function problems other than keeping physically and mentally active.”